On the Relationship between Semiconductor Manufacturing Volume, Yield, and Reliability

Transcription

1 On the Relationship between Semiconductor Manufacturing Volume, Yield, and Reliability Microelectronics Reliability & Qualification Working Meeting February 8, 2017 Dr. Jeffrey Siddiqui, Dr. John Ortega, Mr. Brian Albus Reliability Team, Microelectronics Test Branch, Defense Microelectronics Activity (DMEA) 23-Feb-17 Page-1

2 Outline Motivation Defining Volume Reliability Bathtub Curve Reliability and Yield Reliability Best Practices by Volume Conclusions 23-Feb-17 Page-2

3 Motivation Generally accepted: High Volume (HV) High Yield High Reliability Model for semiconductor suppliers to high demand consumer markets Potentially concerning misconception: Low Volume (LV) Low Yield Low Reliability Can incorrectly be concluded if one applies HV practices to a LV line In reality, LV manufacturers have evolved different reliability best practices Reliability Group has been engaged to explore and clarify the links between volume, yield, and reliability Important to educate key decision makers in industry and government so that they can make the most informed decisions with respect to funding and policy 23-Feb-17 Page-3

4 Defining Volume We discuss volume as manufacturing volume or the amount of products that can be generated by a manufacturing line High Volume (HV) Moore s Law High demand commercial electronics market Short market windows Low Volume (LV) Niche Markets Military, Medical, Aerospace, Automotive, etc. Harsh environments Longer lifetimes More critical consequences with respect to reliability failures Both suppliers are required to provide reliable product 23-Feb-17 Page-4

5 Yield Yield is the percentage of product that functions correctly at the conclusion of manufacturing Determined by end-of-line electrical testing (aka yield testing) Yield is limited by defects created during manufacturing Figurative semiconductor wafer (chips failing yield testing highlighted in red) 23-Feb-17 Page-5

6 Reliability: The Bathtub Curve [Adapted from McPherson Reliability Physics and Engineering] Looking for links between reliability, yield, and volume 23-Feb-17 Page-6

7 Bathtub Curve: Early Life Early Life [Adapted from McPherson Reliability Physics and Engineering] Initially high declining failure rate Early life failures which must be addressed before fielding a product Here is where the link between yield and reliability can be found Manipulating this link is where HV and LV manufacturers have evolved different engineering practices 23-Feb-17 Page-7

8 The Link: Defects Early life failures and yield failures have the same root cause Defects: Any non-ideality introduced during the fabrication process Particles, voids, non-uniformity, contamination, misalignments, etc. Particle example below Example: Figurative particles defects [Adapted from Shirley IRPS 1995 ] Defect size density relationships [Adapted from Shirley 1995 and Wakai et al. RAMS 2008] 23-Feb-17 Page-8

9 Qualitative Analysis Yield Failures and Early Life Reliability failures share a common root cause Manufacturing defects Relationship Yield failure defects (D Y ) and Early Life failure defects (D EL ) share common sources while differing in size or impact on the circuit How do you improve yield (product you sell)? How do you improve early life reliability yield (product returns)? Option 1: Reduce the defects (Yield Learning) Option 2: Don t deliver the defects (Screening) 23-Feb-17 Page-9

10 Yield and Early Life Reliability Defects Yield (Y) Function of the density of yield failure causing defects (D Y ) Y = M exp ( D Y A) Early Life reliability (R EL ) Function of the density of early life failure causing defects (D EL ) R EL = exp ( D EL A) 23-Feb-17 Page-10 [Kuper IRPS 1996 ]

11 Early Life Reliability Y = M exp( D Y A) R EL = exp D EL A Link between Y and Y r... α = D EL D Y R EL = Y M α Original wafer before yield learning or screening 23-Feb-17 Page-11

12 Early Life Reliability Y = M exp( D Y A) R EL = exp D EL A Link between Y and Y r... α = D EL D Y R EL = Y M α 23-Feb-17 Page-12

13 Early Life Reliability Y = M exp( D Y A) R EL = exp D EL A Link between Y and Y r... α = D EL D Y R EL = Y M α 23-Feb-17 Page-13

14 Early Life Reliability Y = M exp( D Y A) R EL = exp D EL A They Both Work! Link between Y and Y r... α = D EL D Y R EL = Y M α 23-Feb-17 Page-14

15 High Volume Approach to Early Life Reliability Global consumer electronics business case: maximize saleable product per time when in profit generating market window Yield learning maximizes saleable product per wafer High volume and throughput, required by business case, lead to faster learning cycles and more return on yield learning investment Efforts reduce both D Y and D EL Cost of yield learning recouped by revenue from selling high volume of products through high yield llines In order to meet market window leading edge, screening practices used to sell product from lots with lower yields Minimizing time-to-market and maximizing saleable product are both advantageous HV Manufacturers will use a mix of Yield Learning and Screening, with a preference for Yield Learning 23-Feb-17 Page-15

16 Low Volume Approach to Early Life Reliability With fewer resources, the large investment in yield learning makes less sense The large volumes to learn quickly and efficiently do not exist Yield learning still undertaken, just to less extent than for HV manufacturers Screening instead is the preferred method to deliver product with high early life reliability Screening increases scrap, reduces throughput, and thus increases cost Screening applied on per product basis allowing costs to be charged only to customers willing to pay Product that is delivered early life reliability required by customer Niche market customers are willing to wait and pay for added inspection time and increased cost of screening 23-Feb-17 Page-16

17 Conclusions: Volume, Yield, and Reliability Bathtub curve provides proper context to understand this topic The often referenced link between yield and reliability is between yield and early life reliability The link is defects Defects can be addressed by a mix of yield learning and screening engineering practices Economics and market factors drive HV and LV manufacturers to choose a different mix of engineering resources, which do have an effect on yield and reliability Both HV and LV manufactures can successfully manufacture highly reliable products 23-Feb-17 Page-17

18 The End 23-Feb-17 Page-18

19 Back Matter Appendix A: References 23-Feb-17 Page-19

20 Appendix A: References F. Kuper, J. van der Pol, E. Ooms, T. Johnson, R. Wijburg, W. Koster and D. Johnston, "Relation between yield and reliability of integrated circuits: experimental results and application to continuous early failure rate reduction programs," Reliability Physics Symposium, th Annual Proceedings., IEEE International, pp , N. Wakai, Y. Kobira and H. Egawa, "Consideration of Burn-In Acceleration and Effective Screening Procedure in Latest System LSI," Reliability and Maintainability Symposium, RAMS Annual, pp , J. W. McPherson, Reliability Physics and Engineering, New York: Springer Cham Heidelberg, H. H. Huston and C. P. Clark, "Reliability Defect Detection and Screening During Processing - Theory and Implementation," Reliability Physics Symposium th Annual Proceedings., International, pp , S. Salemi, L. Yang, J. Dai, J. Qin and J. B. Bernstein, Physics-of-Failure Based Handbook of Microelectronic Systems, Reliability Information Analysis Center, C. G. Shirley, "A Defect Model of Reliability," Reliability Physics Symposium 1995, Tutorial. J. van der Pol, E. Ooms, T. van 't Hof and F. Kuper, "Impact of Screening of Latent Defects at Electrical Test on the Yield- Reliability Relation and Application to Burn-in Elimination," International Reliability Physics Symposium, Reno, L. Milor, "A Survey of Yield Modeling and Yield Enhancement Methods," IEEE Transactions on Semiconductor Manufacturing, vol. 26, no. 2, May 2013, pp , C. Weber, "Yield Learning and the Sources of Profitability in Semiconductor Manufacturing and Process Development," IEEE Transactions on Semiconductor Manufacturing, vol. 17, no. 4, November 2004, pp , E. Wang and R. Akella, "Resource Allocation for Yield Learning in Semiconductor Manufacturing," Advanced Semiconductor Manufacturing Conference and Workshop, ASMC 95 Proceedings. IEEE/SEMI 1995, pp , R. Rajsuman, "Iddq Testing for CMOS VLSI," Proceedings of the IEEE, vol. 88, no. 4, April 2000, pp , K. Kim, W. Kuo and W. Luo, " A relation model of gate oxide yield and reliability," Microelectronics Reliability, vol. 44, pp , K. Flamm, "Moore's Law and the Economics of Semiconductor Price Trends," in Productivity and Cyclicality in Semiconductors: Trends, Implications, and Questions -- Report of a Symposium, National Research Council of the National Academies, 2004, pp R. D. J. Heller, " Near Neighbor Sort Yield and Wafer Sort Yield Impact on Product Burn-In and a Time Dependent Reliability Study," in International Reliability Physics Symposium, Pasadena, CA, M. White and J. Bernstein, Microelectronics Reliability: Physics-of-Failure Based Modeling and Lifetime Evaluation, NASA Jet Propulsion Laboratory, Pasadena, Feb-17 Page-20